• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1156-1165
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• 2017

A high performance interleaved bridgeless boost power factor correction (PFC) rectifier operating under the critical current conduction mode (CrM) is proposed in this paper to improve the efficiency and system performance of various applications, such as nano-grid systems. By combining the interleaved technique with the bridgeless topology, the circuit contains two independent branches without rectifier diodes. The branches operate in interleaved mode for each respective half-line period. Moreover, when operating in CrM, all the power switches take on soft-switching, thereby reducing switching losses and raising system efficiency. In addition, the input current flows through a minimum amount of power devices. By employing a commercial PFC controller, an effective control scheme is used for the proposed circuit. The operating principle of the proposed circuit is presented, and the design considerations are also demonstrated. Simulations and experiments have been carried out to evaluate theoretical analysis and feasibility of the proposed circuit.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.467-475
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• 1999

This paper presents an analysis method of a forward converter, using both the finite element method considering the external circuit and a state variables equation. The converter operates at 50kHz and its one period is divided into two modes for the simplicity of the analysis. In the first mode, the switching transistor turns on and an input power is transferred into the load by the electromagnetic conversion action of a ferrite transformer. In the second mode, the switching transistor turns off and the stored energy in an inductor is delivered to the load, and the transformer core is demagnetized by the reset winding current. In this paper, time-stepping finite element method taking into account the on-state electrical circuit of the converter in used to analyze both the electrical circuit and electromagnetic field of the magnetic device during the first mode and the demagnetization period of the transformer core. Then a state variables equation for the circuit which the inductor current flows is constituted and solved during the second mode. As a result, the simulation results have been good agreement with the results obtained form experiment.

• Journal of Drive and Control
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• v.18 no.4
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• pp.52-58
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• 2021

The variable structure controller is designed such that in sliding mode, the system moves along the switching plane in the vicinity of the switching plane, thus it is robust because it is not affected by the parameter fluctuations of the plant. However, a controller based on a variable structure may not meet the desired performance when it is commanded to track any input or is exposed to disturbances. This study proposes a sliding mode controller that follows the IVSC (Integral Variable Structure Control) approach with ELO (Extended Luenberger observer) to solve this problem. The proposed sliding mode control is applied to the velocity control of the hydraulic motor. The sliding plane was determined by the pole placement, and the control input was designed to ensure the existence of the sliding mode. The feasibility of modeling and controller are reviewed by comparing with conventional proportional-integral control through computer simulation using MATLAB software and experimenting on the cases of significant plant parameter fluctuations and disturbances.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.138-146
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• 2019

In this paper, we proposed a soft-switched synchronous buck converter, which can perform charging the battery. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss, resulting in small conduction loss, also. In this reason, the efficiency of the converter can be greatly improved even in high frequency. The size and weight of the converter can be reduced by high frequency operation of the converter. In this paper, we designed a battery charger with a switching frequency of 100 kHz. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery charger had soft switching characteristics. The simulation results for transient response to charge current for the designed converter show that the converter responds to charge current commands quickly within 0.05 ms.

• Journal of Power Electronics
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• v.6 no.2
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• pp.95-103
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• 2006

In this paper, a novel prototype of auxiliary switched capacitor assisted voltage source soft switching PWM Single-Ended Push Pull (SEPP) series capacitor compensated load resonant inverter with two auxiliary edge resonant lossless inductor snubbers is proposed and discussed for small scale consumer high-frequency induction heating (IH) appliances. The operation principle of this inverter is described by using switching mode equivalent circuits. The newly developed multi resonant high-frequency inverter using trench gate IGBTs can regulate its output AC power via constant frequency edge-resonant associated soft switching commutation by using an asymmetrical PWM control or duty cycle control scheme. The brand-new consumer IH products which use the newly proposed edge-resonant soft switching PWM-SEPP type series load resonant high-frequency inverters are evaluated using power regulation characteristics, actual efficiency vs. duty cycle and input power vs. actual efficiency characteristics. Their operating performance compared with some conventional soft switching high-frequency inverters for IH appliances is discussed on the basis of simulation and experimental results. The practical effectiveness of the newly proposed soft switching PWM SEPP series load resonant inverter is verified from an application point of view as being suitable for consumer high-frequency IH appliances.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.7
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• pp.374-379
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• 2006

The switch mode power supply is a source of EMI with other equipment as well as with its own proper operation because of rapid changes in voltages and currents within a switching converter. The EMI is transmitted in two forms: radiated and conducted. Conducted noise consists of two categories known as the differential mode and the common mode. Common mode noise current is a major source of EMI in the switch mode Power supply. Recently, a current balancing technique has been studied to reduce the common mode noise. This paper investigates the reduction of common mode noise according to a node expansion of the switch mode power supply which is based on a current balancing technique. In this paper, seven PCB patterns of the forward converter are manufactured and experimented.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.667-670
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• 2009

This paper presents an LMI-based method to design a sliding mode controller for a multivariable uncertain system with a polytopic model. In terms of LMIs an existence condition of a sliding surface is derived. And a switching feedback control law is given. Finally, a numerical design example is given to show that the proposed method can be better than the existing results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.44-48
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• 2010

This paper presents an LMI-based method to design an integral sliding mode controller for an uncertain system with a polytopic model. The uncertain system under consideration may have mismatched parameter uncertainties in the state matrix as well as in the input matrix. Using LMIs we derive an existence condition of a sliding surface. And we give a switching feedback control law.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.138-141
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• 2011

This paper presents an LMI-based method to design an output feedback integral sliding mode controller for a class of uncertain systems. Using LMIs we derive an existence condition of a sliding surface. And we give a switching feedback control law. Finally, we give a numerical design example in order to show the effectiveness of the proposed method.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.397-398
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• 2013

Fairchild Green Mode off line buck switch for low standby power consumption and high reliability is presented. By reducing operating current and optimizing switching frequency, 20mW power consumption is achieved. High performance trans-conductance amplifier and green mode function improve the ripple and regulation in the output voltage. The conventional $FPS^{TM}$ buck and novel Fairchild buck switch are compared to show the improvement of performance. Experimental results are showed using 2W evaluation board.